Balance assessment in selected stages of Parkinson’s disease using trend change analysis

Abstract

Background Balance disorders in patients diagnosed with Parkinson’s disease (PD) are associated with a change in balance-keeping strategy and reflex disorders which regulate the maintenance of vertical body posture. Center of foot pressure (COP) displacement signals were analyzed during quiet standing experiments to define such changes. The research aimed to apply stock exchange indices based on the trend change analyses to the assessment of a level of the Parkinson disease progression on the grounds of the analysis of the COP signals. Methods 30 patients in two stages of PD, 40 elderly participants, and 20 individuals at a young age were studied. Each person was subjected to 3 measurements with open and closed eyes. A technical analysis of the COP displacement signal was performed, and the following quantities were determined: indices related to the number of trend changes (TCI), indices defining a mean time (TCI_dT), and mean displacement (TCI_dS) and mean velocity (TCI_dV) between such changes. Results The results indicate a higher TCI value for PD than for aged-matched control group (p < 0.05). In the case of PD patients, there was also an increase in the TCI_dS value by 2–5 mm, which mainly contributed to the increase in TCI_dV. Statistically significant differences for the TCI_dT values occurred between all groups in which differences in the average COP velocity were noted. Conclusions The TCI and TCI_dV results obtained for the healthy participants enabled the development of indices supporting PD diagnostics. The causes of the TCI_dV changes in patients were determined, i.e., whether they resulted from an increase in the TCI_dT or TCI_dS between the moments of trend changes indicated by the developed algorithm. The developed methodology provides new information on the impact of PD on the strategy of maintaining balance, which was impossible to obtain using currently used analyses. Trial registration The conducted research is an observational study and does not include a health care intervention. Participants gave their consent to participate in the research and the procedure was approved by the Institutional Bioethics Committee.

Trend Change Analysis of postural balance in Parkinson`s disease discriminates between medication state

“…We found a higher number of TCIs and smaller TCI_dT values in PDoff compared to PDon. This is coherent with previous results obtained for COP measurements showing an increase in TCIs and reduction of TCI_dT in pwPD compared to healthy individuals [37]. In our view, this perspective also aligns with a pathomechanistic standpoint.…”

Trend change analysis in the assessment of body balance during posture adjustment in reaction to anterior-posterior ground perturbation

“…Positive verification of the hypothesis may allow the formulation of a new method supporting assessment of PA. The reliability and validity of trend changes parameters was confirmed in previous research [ 18 , 19 ].…”

“…What interesting opposite changes in balance strategy were observed in research comparing results obtained for people with Parkinson Disease and healthy participants during normal standing [ 18 ]. Measurements revealed higher values of Vcop and TCI_dV, just like in measurements described in this article, but smaller values of TCI_dT in PD group with no statistically significant differences in TCI_dS.…”

“…The method of trend change analysis comes from technical analysis of signals, which is based on moving averages with exponential weights. To begin with, the algorithm employs the MACD (Moving Average Convergence Divergence) indicator calculation process in its initial phase [ 18 , 19 ]. This algorithm assesses relationships linked to the convergence and divergence of moving averages of a measured signal—in the study it is COP signal.…”

“…A new advancement in postural analysis is the application of trend change analysis (TCA). This method can identify rapid adjustments and an elongation in the displacement between consecutive postural adjustments [ 18 , 19 ]. Borrowed from strategies initially used in stock market analyses, TCA aids in measuring postural adjustments in both the front-to-back (A/P) and side-to-side (M/L) directions.…”